It is known that common salt is made by depositing sodium chloride from sea water but, recently, natural salt, i.e., salt containing not only sodium chloride but also other sea water components such as minerals, has been attracted attention.
It is said that sea water contains almost the same components as those of human blood and, from this viewpoint, natural salt is considered preferred for human consumption.
As a result, the number of people who use natural salt for food is increasing and "salt application health method" in which a natural salt is applied to a human body and "salt bathing" in which a natural salt is added to bath water have been proposed, not only for health and cosmetic purposes but also as therapeutics of atopic dermatitis and so on.
As a method for making a natural salt, a method is known in which a crude salt, which is a kind of natural salt obtained by evaporating water from sea water by the heat of the sun, is dissolved in water and then heated at a temperature of 140 to 180.degree. C. for 6 to 12 hours.
The above method has the problems that the heating requires a large amount of energy and a large apparatus and the salt becomes unnatural by deviation of the components or removal of bittern, particularly magnesium and calcium.
The present invention, considering the above problems, has the object to provide a salt making method and apparatus which are simple in construction and can make a natural salt.